What is the most appropriate response by a nurse when a patient expresses concerns over having black stool?

When a patient expresses concerns about having black stool, it is important to consider potential dietary or medication-related causes. The presence of black stool could be linked to the consumption of iron supplements, which are known to cause this change in stool color due to the iron content. Inquiring whether the patient is taking iron supplements allows the nurse to identify a common and benign reason for the symptom, which can alleviate the patient's anxiety.

Addressing this concern promptly can help differentiate between harmless dietary factors and more serious underlying conditions such as gastrointestinal bleeding, which could also cause black stool due to the presence of digested blood. This response is informative and relevant, helping the nurse gather pertinent information while providing reassurance about a common cause.